Discontinuous transmission for a mobile phone network node

ABSTRACT

A mobile phone network node may determine traffic load associated with a mobile phone network and initiate discontinuous transmission at a frame level, based at least in part upon, determining that the traffic load is less than a first threshold. The mobile phone network node may further initiate discontinuous transmission at a subframe level, based at least in part upon, determining that the traffic load is greater than the first threshold and less than a second threshold and initiate discontinuous transmission at a symbol level, based at least in part upon, determining that the traffic load is greater than the second threshold.

PRIORITY

This application is a continuation, under 35 U.S.C. § 120, of U.S.application Ser. No. 14/279,082 filed May 15, 2014, entitled“DISCONTINUOUS TRANSMISSION FOR A MOBILE PHONE NETWORK NODE” which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

Particular embodiments relate generally to wireless communications andmore particularly to discontinuous transmission for a mobile phonenetwork node.

BACKGROUND

In a wireless network, a wireless device may communicate with one ormore radio access nodes to send and/or receive information, such asvoice traffic, data traffic, control signals, etc., creating networktraffic load. The traffic load pattern varies based on a variety offactors. For example, the network traffic load is different during daytime and night time. It may be different in summer time and in wintertime and it may be different during normal days and holidays or specialevent days. Too few cells will cause a coverage problem as well asadditional problems when the traffic load is high. Too many cells willcause waste when the traffic load is low and will generate interferenceto neighbor cells as well as negatively impacting the environment due toradiation and excessive electricity use.

Various unsuccessful attempts have been made to deal with these issues.For example, a popular solution is to combine the cells when the trafficload is low. However, the problem for this potential solution is thatthe coverage will be reduced. Moreover, this potential solution alsorequires cell shut down and startup which is wasteful and burdensome.

SUMMARY

According to some embodiments, a mobile phone network node may beoperable to determine traffic load associated with a mobile phonenetwork and initiate discontinuous transmission at a frame level, basedat least in part upon, determining that the traffic load is less than afirst threshold. The mobile phone network node is further operable toinitiate discontinuous transmission at a subframe level, based at leastin part upon, determining that the traffic load is greater than thefirst threshold and less than a second threshold and initiatediscontinuous transmission at a symbol level, based at least in partupon, determining that the traffic load is greater than the secondthreshold.

In some embodiments, the mobile phone network node may determine whethera symbol includes a reference signal and may allocate data to the symbolthat includes a reference signal. According to some embodiments, themobile phone network node may determine whether a symbol includes areference signal and use the symbol for discontinuous transmission ifthe symbol does not include a reference signal.

According to some embodiments, a discontinuous transmission method foran Evolved Node B may include determining traffic load associated with amobile phone network and initiating discontinuous transmission at aframe level, based at least in part upon, determining that the trafficload is less than a first threshold. The method may also includeinitiating discontinuous transmission at a subframe level, based atleast in part upon, determining that the traffic load is greater thanthe first threshold and less than a second threshold and initiatingdiscontinuous transmission at a symbol level, based at least in partupon, determining that the traffic load is greater than the secondthreshold.

In at least some embodiments, a discontinuous transmission system mayinclude a memory and a processor. The processor may be operable todetermine traffic load associated with a mobile phone network andinitiate discontinuous transmission at a frame level, based at least inpart upon, determining that the traffic load is less than a firstthreshold. The processor is further operable to initiate discontinuoustransmission at a subframe level, based at least in part upon,determining that the traffic load is greater than the first thresholdand less than a second threshold and initiate discontinuous transmissionat a symbol level, based at least in part upon, determining that thetraffic load is greater than the second threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating an example of a network;

FIG. 2 is a block diagram illustrating embodiments of a radio networknode;

FIG. 3 is a block diagram illustrating embodiments of a wireless device;

FIG. 4 is a block diagram illustrating embodiments of a core networknode;

FIG. 5 is a an example downlink resource element diagram;

FIG. 6 is a flow chart illustrating example embodiments of datascheduling;

FIG. 7 is a graph illustrating example traffic load estimation;

FIG. 8 is a graph illustrating example data that may be used in apriority lookup table;

FIG. 9 is a block diagram illustrating embodiments of mapping resourceelements to symbols;

FIG. 10 is a flow chart illustrating embodiments of discontinuoustransmission determination for subframes and frames;

FIG. 11 is a diagram illustrating radio frame and subframe levels; and

FIG. 12 is a flowchart illustrating example embodiments of discontinuoustransmission for a mobile phone network node.

DETAILED DESCRIPTION

Wireless device communication with radio network nodes generates networktraffic load. Various factors may dictate what the traffic load may beat a particular point in time. To conserve resources, cells may beselectively turned on or off. However, too few cells cause a coverageproblem as well as additional problems when the traffic load is high. Onthe other hand, too many cells waste resources when the traffic load islow, will generate interference to neighboring cells, and may negativelyimpact the environment due to radiation and excessive electricity use.

Particular embodiments of the present disclosure may provide solutionsto these and/or other problems. For example, a method of discontinuoustransmission (DTX) may be implemented in a radio network node (e.g., aneNodeB) in a mobile phone network (e.g., LTE mobile communicationnetwork). DTX may be implemented in multiple levels. The minimum DTXlevel is in the orthogonal frequency-division multiplexing (OFDM) symbollevel. If too many symbols are in DTX, then DTX at the subframe or framelevel can be used. Because of this approach, the signaling may remainsimple. Whether the DTX is in the OFDM symbol, subframe, or frame levelswill depend on the traffic load at the radio network node. For example,when network traffic is low during the night time, non-transmission atthe subframe or frame level can be used. However, when network trafficis higher but there are some unused resource elements in some of thesubframes, then DTX in one or more OFDM symbols in a subframe may beconsidered.

When frame level. DTX is used, DTX at the subframe and symbol level canstill be used. For example, when frame level DTX is used, DTX at thesubframe and/or symbol level can also be used for the frames that werenot used for DTX. When subframe level DTX is used, DTX at the symbollevel can still be used. As an example, when subframe level DTX is used,DTX at the symbol level may be used for subframes that were not used forDTX. The traffic load may be estimated by using an algorithm presentedin this disclosure. Selection of the DTX levels (e.g., symbol, subframe,or frame level) is based on the estimated traffic load. When DTX at thesubframe or frame level is selected, the information may be signaled bya broadcast signal message. When the symbol level DTX level is selected,the information may be signaled by a downlink control information (DCI)message transmitted on the physical downlink control channel (PDCCH) inthat subframe. The scheduler will allocate the resources to the trafficdata packets on the non-DTX symbols and the non-DTX subframes to framesaccordingly.

Particular embodiments are described in FIGS. 1-12 of the drawings, likenumerals being used for like and corresponding parts of the variousdrawings.

FIG. 1 is a block diagram illustrating an example of a network 100 thatincludes one or more wireless communication devices 110 and a pluralityof network nodes. The network nodes include radio network nodes 120 andcore network nodes 130. In the example, wireless communication device110 communicates with radio network node 120 b over a wirelessinterface. For example, wireless communication device 110 transmitswireless signals to radio network node 120 b and/or receives wirelesssignals from radio network node 120 b. The wireless signals containvoice traffic, data traffic, control signals, and/or any other suitableinformation.

A radio network node 120 refers to any suitable node of a radio accessnetwork/base station system. Examples include a radio access node (suchas a base station or eNodeB) and a radio access controller (such as abase station controller or other node in the radio network that managesradio access nodes). Radio network node 120 interfaces (directly orindirectly) with core network node 130. For example, radio network node120 interfaces with core network node 130 via an interconnecting network125. Interconnecting network 125 refers to any interconnecting systemcapable of transmitting audio, video, signals, data, messages, or anycombination of the preceding. Interconnecting network 125 may includeall or a portion of a public switched telephone network (PSTN), a publicor private data network, a local area network (LAN), a metropolitan areanetwork (MAN), a wide area network (WAN), a local, regional, or globalcommunication or computer network such as the Internet, a wireline orwireless network, an enterprise intranet, or any other suitablecommunication link, including combinations thereof.

Core network node 130 manages the establishment of communicationsessions and various other functionality for wireless communicationdevice 110. Wireless communication device 110 exchanges certain signalswith core network node 130 using the non-access stratum layer. Innon-access stratum (NAS) signaling, signals between wirelesscommunication device 110 and core network node 130 pass transparentlythrough radio network nodes 120. Examples of radio network node 120,wireless communication device 110, and core network node 130 aredescribed with respect to FIGS. 2, 3, and 4 respectively.

It should be noted that although the present disclosure may discuss oneor two antenna examples, this disclosure is also applicable to networksinvolving three or more antennas.

FIG. 2 is a block diagram illustrating embodiments of a radio networknode. In the illustration, radio network node 120 is shown as a radioaccess node, such as an eNodeB, a node B, a base station, a wirelessaccess point (e.g., a Wi-Fi access point), a low power node, a basetransceiver station (BTS), transmission points, transmission nodes,remote RF unit (RRU), remote radio head (RRH), etc. Other radio networknodes 120, such as one or more radio network controllers, may beconfigured between the radio access nodes and core network nodes 130.These other radio network nodes 120 may include processors, memory, andinterfaces similar to those described with respect to FIG. 2, however,these other radio network nodes might not necessarily include a wirelessinterface, such as transceiver 210.

Radio access nodes are deployed throughout network 100 as a homogenousdeployment, heterogeneous deployment, or mixed deployment. A homogeneousdeployment generally describes a deployment made up of the same (orsimilar) type of radio access nodes and/or similar coverage and cellsizes and inter-site distances. A heterogeneous deployment generallydescribes deployments using a variety of types of radio access nodeshaving different cell sizes, transmit powers, capacities, and inter-sitedistances. For example, a heterogeneous deployment may include aplurality of low-power nodes placed throughout a macro-cell layout.Mixed deployments include a mix of homogenous portions and heterogeneousportions.

Radio network node 120 includes one or more of transceiver 210,processor 220, memory 230, and network interface 240. Radio network node120 may also include data queue 250, traffic engine 260, message engine270, scheduling engine 280, and/or DTX engine 290.

Transceiver 210 facilitates transmitting wireless signals to andreceiving wireless signals from wireless communication device 110 (e.g.,via an antenna), processor 220 executes instructions to provide some orall of the functionality described above as being provided by a radionetwork 120, memory 230 stores the instructions executed by processor220, and network interface 240 communicates signals to backend networkcomponents, such as a gateway, switch, router, Internet, Public SwitchedTelephone Network (PSTN), other radio network nodes 120, core networknodes 130, etc.

Processor 220 includes any suitable combination of hardware and softwareimplemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions ofradio network node 120. In some embodiments, processor 220 includes, forexample, one or more computers, one or more central processing units(CPUs), one or more microprocessors, one or more applications, and/orother logic.

Memory 230 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 230 includecomputer memory (for example, Random Access Memory (RAM) or Read OnlyMemory (ROM)), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation.

In some embodiments, network interface 240 is communicatively coupled toprocessor 220 and refers to any suitable device operable to receiveinput for radio network node 120, send output from radio network node120, perform suitable processing of the input or output or both,communicate to other devices, or any combination of the preceding.Network interface 240 includes appropriate hardware (e.g., port, modem,network interface card, etc.) and software, including protocolconversion and data processing capabilities, to communicate through anetwork.

Radio network node 120 may include data queue 250. Data queue 250 may beany combination of software, hardware, and/or firmware that allows radionetwork node to queue electronic data. In certain embodiments, dataqueue 250 may be stored in memory 230. In certain embodiments, data indata queue 250 may be queued for allocation to an OFDM symbol andsubsequent transfer to wireless communication device 110. In at leastsome embodiments, a priority may be associated with the data stored indata queue 250. For example, portions of data in data queue 250 may beconsidered “high priority,” “low priority,” or “medium priority.”

Radio network node 120 may use scheduling engine 280 to schedule data indata queue 250 for transfer to wireless communication device 110.Generally, scheduling engine 280 may allocate resource elements totraffic data packets on symbols, subframes, and frames. Morespecifically, scheduling engine 280 may be any combination of software,hardware, and/or firmware that allows radio network node 120 to scheduledata in data queue 250 for transmission. In certain embodiments,scheduling engine 280 may map resource elements to OFDM symbols.According to some embodiments, scheduling engine 280 may schedule thetraffic on the resource elements of a particular subframe.

In at least some embodiments, the data allocation performed byscheduling engine 280 is based on OFDM symbols. Considering the downlinkcontrol channel allocation (one to four symbols of the first slot ofeach subframe) and downlink reference signal allocation, the dataallocation for user traffic may start from symbols used for transmittingthe reference signals (symbol 0 and 4 for every slot), then move to thesymbols used for transmitting data only. Scheduling engine 280 is alsocapable of re-queuing data back into data queue 250 in order to betransmitted in a subsequent (e.g., next) scheduling time slot if thesymbol is not fully allocated and the priority of the data in thatsymbol is not high enough.

Scheduling engine 280 may also determine data priority associated withdata in data queue 250. For example, data priority may be based onquality of service (QoS) input, channel condition(s), and data waitingtime associated with data in data queue 250. Example priorities may behigh, medium and low. The data allocation, at least in some embodiments,may start from high priority, then medium priority, and then lowpriority. The actual priority of data may be presented as a real value.FIG. 8, discussed below, is an example lookup table that may be used forpriority determination.

Another function of scheduling engine 280 may be resource element (RE)estimation. Scheduling engine 280 may determine how many REs are neededfor data located in data queue 250 at a particular time. In someembodiments, data allocation may be per RE instead of per physicalresource block (PRB). An example algorithm for calculating the number ofREs may be determining the suitable modulation and coding scheme (MCS)and transport block size (TBS). The MCS and TBS are determined by thecombination of RF channel estimation, link adaptation, and QoSrequirements. These are determined per user and per priority queue(e.g., data queue 250). The number of REs to be allocated can then becalculated based on the MCS, TBS, and the prioritized data in data queue250.

Scheduling engine 280 may also map REs to symbols. An example of howscheduling engine 280 may map REs to symbols is discussed further belowwith regard to FIG. 9.

Radio network node 120 may also include traffic engine 260. Generally,radio network node 120 may use traffic engine 260 to determine trafficload associated with network 100. More specifically, traffic engine 260may be any combination of software, hardware, and/or firmware thatallows radio network node 120 to determine a traffic load estimation. Incertain embodiments, traffic engine 260 may calculate a daily averagetraffic load which may be a calculated traffic load over the course of acertain number of days. According to some embodiments, traffic engine260 may calculate a current traffic load which may be a calculatedtraffic load over the course of a certain number of seconds. Trafficengine 260 may also use calculated traffic loads to calculate apredicted traffic load. For example, traffic engine 260 may use thefollowing function to calculate a predicted traffic load:“f(t)=a*f_d(t)+(1−a)*f_i(t)” where “f_d(t)” represents the daily trafficload, “f_i(t)” represents instant traffic load at a current time “t,”and “a” is a smoothing factor between 0 and 1.

Radio network node 120 may also include message engine 270. Generally,message engine 270 may be used by radio network node 120 to communicateany suitable message. More specifically, message engine 270 may be anycombination of software, hardware, and/or firmware that allows radionetwork node 120 to communicate a message to any component of network100. For example, message engine 270 may generate a PDCCH message, abroadcast message, a synchronization message, a signal message, and/orany other message suitable for a particular purpose. In someembodiments, message engine 270 may alter and/or set one or more bits ina message. According to certain embodiments, message engine 270 mayalter (e.g., by removing or adding) the total number of bits in amessage.

Radio network node 120 may also include DTX engine 290. Generally, radionetwork node 120 may use DTX engine 290 to make various decisionsregarding the implementation of DTX at the symbol, subframe, and/orframe levels. More specifically, DTX engine 290 may be any combinationof software, hardware, and/or firmware that allows radio network node120 to determine at what level DTX may be implemented and how DTX shouldbe implemented. For example, DTX engine 290 may use traffic engine 260to determine a predicted traffic load estimation to determine what DTXschemes should be utilized (e.g., symbol-based, subframe-based, orframe-based). If DTX engine 290 determines traffic load is low, it mayselect frame-based DTX. Otherwise, DTX engine 290 may consider usingsubframe-based or symbol-based DTX.

In one embodiment, DTX engine 290 may determine subframe and frame DTXbased on traffic load. For example, DTX engine 290 may utilize trafficengine 260 to calculate a percentage of OFDM symbols used in one frameto indicate traffic load. The following table shows various trafficstates and their corresponding thresholds and parameters:

TABLE 1 Example traffic load states and corresponding thresholds andparameters Wait- Thresh- ing Hys- State old Time teresis Description 0TH(0) WT(0) HY(0) This state corresponds to high traffic load, and theremay not be DTX in subframe or frame in this state. At a high trafficload, DTX may be initiated at the symbol level. When the measuredtraffic load is below (TH(0) − HY(0)) for WT(0) time, it will move tostate 1. Otherwise, it will stay in this state. k = TH(k) WT(k) HY(k)This state corresponds to 1, medium traffic load. 2^(k) number 2, ofsubframes are DTXed, in this 3 state, where k may be 1, 2, or 3. Whenthe measured traffic load is below (TH(k) − HY(k)) for WT(k) time, itwill move to state = k + 1. When the measured traffic load is above(TH(k) + HY(k)) for WT(k) time, it will move to state = k − 1. If themeasured traffic load is between (TH(k) − HY(k)) and (TH(k) + HY(k)), itwill stay in this state. 4 TH(4) WT(4) HY(4) This state corresponds tolow traffic load. Odd frames, and up to eight subframes of even framesmay be DTXed in this state. When the measured traffic load is above(TH(4) + HY(4)) for WT(4) time, it will move to state 3. Otherwise, itwill stay in this state.

The DTX determination example in the table above is discussed further inconjunction with FIG. 10 below. Additionally, DTX engine 290 mayimplement DTX at multiple levels. For example, when frame level DTX isused, DTX engine 290 may also implement DTX at the subframe and/orsymbol level for frames that were not used for DTX. As another example,when subframe level DTX is used, DTX engine 290 may also implement DTXat the symbol level for subframes that were not used for DTX. DTX engine290 is operable to implement DTX in any combination as suitable for aparticular purpose.

Other embodiments of radio network node 120 include additionalcomponents (beyond those shown in FIG. 2) responsible for providingcertain aspects of the radio network node's functionality, including anyof the functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove). The various different types of radio access nodes may includecomponents having the same physical hardware but configured (e.g., viaprogramming) to support different radio access technologies, or mayrepresent partly or entirely different physical components.

Some embodiments of the disclosure may provide one or more technicaladvantages. For example, in some embodiments, energy consumption andradiation is reduced, thus limiting green-house gas emissions and globalwarming. Another technical advantage of certain embodiments is that itreduces power consumption of both mobile wireless communication devicesand radio network nodes thereby improving energy efficiency and reducingelectricity costs. Some embodiments provide the advantage of reducinginterference of neighboring cells. Particular embodiments providetechnical advantages without requiring modification to existing mobilewireless communication devices. The granularity for this DTXimplementation ranges from radio frame or subframe level to the symbollevel. This results in the DTX implementation being very flexible andscalable. The implementation of having the flexible symbol level,subframe level, and frame level DTX means that cell reference signalswill remain in the non-DTX subframes, and, thus, mobile wirelesscommunication devices will still be able to easily decode the down-linkinformation. Moreover, because the subframes which have broadcast andsynchronization signals will not be used for DTX subframes, there is noimpact on mobile wireless communication devices to access the network.

Some embodiments may benefit from some, none, or all of theseadvantages. Other technical advantages may be readily ascertained by oneof ordinary skill in the art.

FIG. 3 is a block diagram illustrating embodiments of a wirelesscommunication device. Examples of wireless communication device 110include a mobile phone, a smart phone, a PDA (Personal DigitalAssistant), a portable computer (e.g., laptop, tablet), a sensor, amodem, a machine type (MTC) device/machine to machine (M2M) device,laptop embedded equipment (LEE), laptop mounted equipment (LME), USBdongles, a device-to-device capable device, or another device that canprovide wireless communication. A wireless communication device 110 mayalso be referred to as user equipment (UE), a station (STA), a mobilestation (MS), a device, a wireless device, or a terminal in someembodiments. Wireless communication device 110 includes transceiver 310,processor 320, and memory 330. In some embodiments, transceiver 310facilitates transmitting wireless signals to and receiving wirelesssignals from radio network node 120 (e.g., via an antenna), processor320 executes instructions to provide some or all of the functionalitydescribed above as being provided by wireless communication device 110,and memory 330 stores the instructions executed by processor 320.

Processor 320 includes any suitable combination of hardware and softwareimplemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions ofwireless communication device 110. In some embodiments, processor 320includes, for example, one or more computers, one or more centralprocessing units (CPUs), one or more microprocessors, one or moreapplications, and/or other logic.

Memory 330 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 330 includecomputer memory (for example, Random Access Memory (RAM) or Read OnlyMemory (ROM)), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation.

Other embodiments of wireless communication device 110 includeadditional components (beyond those shown in FIG. 3) responsible forproviding certain aspects of the wireless communication device'sfunctionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the solution described above).

FIG. 4 is a block diagram illustrating embodiments of a core networknode. Examples of core network node 130 can include a mobile switchingcenter (MSC), a serving GPRS support node (SGSN), a mobility managemententity (MME), a radio network controller (RNC), a base stationcontroller (BSC), and so on. Core network node 130 includes processor420, memory 430, and network interface 440. In some embodiments,processor 420 executes instructions to provide some or all of thefunctionality described above as being provided by core network node130, memory 430 stores the instructions executed by processor 420, andnetwork interface 440 communicates signals to an suitable node, such asa gateway, switch, router, Internet, Public Switched Telephone Network(PSTN), radio network nodes 120, other core network nodes 130, etc.

Processor 420 includes any suitable combination of hardware and softwareimplemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions ofcore network node 130. In some embodiments, processor 420 includes, forexample, one or more computers, one or more central processing units(CPUs), one or more microprocessors, one or more applications, and/orother logic.

Memory 430 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 430 includecomputer memory (for example, Random Access Memory (RAM) or Read OnlyMemory (ROM)), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation.

In some embodiments, network interface 440 is communicatively coupled toprocessor 420 and may refer to any suitable device operable to receiveinput for core network node 130, send output from core network node 130,perform suitable processing of the input or output or both, communicateto other devices, or any combination of the preceding. Network interface440 includes appropriate hardware (e.g., port, modem, network interfacecard, etc.) and software, including protocol conversion and dataprocessing capabilities, to communicate through a network.

Other embodiments of core network node 130 include additional components(beyond those shown in FIG. 4) responsible for providing certain aspectsof the core network node's functionality, including any of thefunctionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 5 is an example downlink resource element diagram. Example downlinkresource element diagram 500 is an example of downlink resource elementallocation that may be used by the systems of FIGS. 1, 2, 3, and/or 4.In certain embodiments, downlink resource element diagram 500 may be anexample of resource element allocation performed by scheduling engine280 and/or DTX engine 290. Downlink resource element diagram 500includes subframes 510, slots 520, symbols 530, and subcarriers 540. Inthe example diagram, two subframes 510 are depicted: “subframe 0” and“subframe 1.” Two slots 520 are shown per subframe 510: “slot 0” and“slot 1” for “subframe 0” and “slot 2” and “slot 3” for “subframe 1.”Example downlink resource element diagram 500 also depicts subcarriers540. In this example, twelve subcarriers 540 are depicted numbered 0through 11. Certain symbols may include cell reference signals. Forexample, in FIG. 5, for slot 520 “slot 0,” symbol 530 “0” at subcarrier540 “5” is depicted as containing a reference signal for “ant 0” whichmay be a first antenna. For slot 520 “slot 0,” symbol 530 “0” atsubcarrier 540 “8” is depicted as carrying a reference signal for “ant1” which may be a second antenna. Resource elements not containingreference signals may be used for content (e.g., data or messages)related to PDCCH, physical control format indicator channel (PCFICH),and/or physical hybrid-ARQ indicator channel (PHICH). For examplesymbols 530 1, 2, and 3 of slot 520 “slot 0” is depicted as containingsuch content. In the example diagram, PCFICH, PHICH, and/or PDCCH coulduse any of the first four symbols 530 to transmit content as long as theparticular resource element does not contain a reference signal (e.g.,symbol 530 0 at subcarrier 540 2 as discussed above). In certainembodiments, DTX may not be performed in symbols 530 that contain a cellreference signal. For example, FIG. 5 depicts two symbols 530 in slot520 “slot 0” and two symbols 530 in slot 520 “slot 1” as including cellreference signals. Therefore, in this example, DTX may not be performedin those symbols 530 but may be performed in any of the remaining tensymbols 530 of subframe 520 “subframe 0.”

FIG. 6 is a flow chart illustrating example embodiments of datascheduling. Example method 600 is an example of scheduling that may beperformed using the systems described in FIGS. 1, 2, 3, and/or 4. Atstep 602, data may be received at data queue 250. At step 604, dataprioritization may be determined for the data in data queue 250.Prioritization may be based on the wait time associated with aparticular unit of data, quality of service input, and channelconditions. Next, at step 606, a number of resource elements may beestimated for allocating data in data queue 250. This may be based on anopen loop (OL) adjustment, determined at step 608, a measure channelquality indication (CQI), determined at step 610, and an MCS estimation,determined at step 612. Resource element mapping may then be performedat step 614 based on priority of the data in data queue 250. Prioritywill be given to high priority data first, then medium priority, thenlow priority. At step 616, a scheduling decision may be made. In certainembodiments, this decision may be made using scheduling engine 280and/or DTX engine 290. For example, certain symbols mapped to certaindata (e.g., high, medium, and/or low priority data) may be scheduled fora current transmission time interval (TTI) at step 618 while it may bealso determine, at step 620, certain symbols mapped to only low prioritydata may not be scheduled. As a result of the symbol not beingscheduled, at step 622, the data originally mapped to the symbol may bere-placed in data queue 250, and at step 624, an associated waiting timefor the data may be updated.

FIG. 7 is a graph illustrating example traffic load estimation. Examplegraph 700 is an example of a traffic load estimation. In certainembodiments, the values of graph 700 may be determined by traffic engine260. Example graph 700 may include, on the y-axis, capacity percentage702 which may represent a traffic capacity percentage associated withnetwork 100. On the x-axis, graph 700 may include time in any suitableunit (e.g., seconds, minutes, hours, etc.) at any suitable interval.Graph 700 includes two curves. Curve 706 is the instant traffic loadwhich represents the current traffic load average for the last certainamount of seconds calculated in function f_i, where the last certainamount of seconds is configurable as suitable for a particular purpose.Curve 708 represents the daily average traffic load calculated infunction f_d, which is calculated from the last certain number of days,wherein the last certain number of days is configurable as suitable fora particular purpose. Graph 700 may also include thresholds 712 and 714.Threshold 712 may be a “low” threshold and threshold 714 may be a “high”threshold. In certain embodiments, when the traffic load is belowthreshold 712, the traffic load is deemed to be “low.” If the trafficload is above threshold 714, then the traffic load is deemed to be“high.” Otherwise, the traffic load may be deemed to be medium.Thresholds 712 and 714 are configurable as suitable for a particularpurpose.

FIG. 8 is a graph illustrating example data that may be used in apriority lookup table. Example graph 800 is example data that may beassociated with a priority lookup table that may be used by the systemsdescribed in FIGS. 1, 2, 3, and/or 4. Example graph 800 includes value802 on the y-axis which may represent a real value associated with datathat may be in data queue 250. Example graph 800 also includes waitingtime 804 on the x-axis which may represent a wait time associated withdata that may be in data queue 250. Curves 806, 808, and 810 representpriority values that may be associated with certain QoS class ofidentifier (QCI). For example, curve 806 may be associated with “QCI Z,”curve 808 may be associated with “QCI Y,” and curve 810 may beassociated with “QCI X.”

FIG. 9 is a block diagram illustrating embodiments of mapping resourceelements to symbols. FIG. 9 depicts an example diagram of how DTX may beimplemented at the symbol level by the systems described in FIGS. 1, 2,3, and/or 4. In certain embodiments, the example DTX implementation maybe performed by scheduling engine 280 and/or DTX engine 290. The examplediagram includes data allocation steps 902, slots 904, and symbols 906.

In the example, it is assumed that the first two symbols 906 (e.g., 0and 1 on slot 904 a) in the current TTI may be used for the PDCCH, whichmeans that the available symbols 906 may be 2 through 6 in slot 904 aand 0 through 6 in slot 904 b. In the example, symbol 906 “4” in slot904 a and symbol 906 “0” and “4” in slot 904 b are depicted as beingused for cell reference signal transfer (depicted as darker squares inthe diagram). Because they are being used for cell reference signaltransfer, these particular symbols 906 will be used (or transmitted)whether or not any other data is allocated to those symbols 906.Therefore, data allocation may begin at symbol 906 “4” of slot 904 a,with the high priority data first, then go to symbol 906 “0” of slot 904b, and then symbol 906 “4” of slot 904 b. If there is still data in dataqueue 250, then the allocation continues at symbol 906 “2” throughsymbol 906 “6” of slot 904 a and then symbol 906 “0” through symbol 906“6” of slot 904 h.

In the example diagram, symbols 906 “2,” “3,” “4,” and “5” in slot 904 aand symbol 906 “0” and symbol 906 “4” in slot 904 b are fully allocateddata, but symbol 906 “6” in slot 904 a) is not fully allocated. If thedata in this symbol 906 is low priority, then the data in symbol 906 “6”of slot 904 a will be retuned back to data queue 250 for the nextscheduling time slot and symbol 906 “6” of slot 904 a may be DTXed. Toreduce inter-cell interference, the symbol level DTX patterns can berandomized for different subframes.

FIG. 10 is a flow chart illustrating embodiments of discontinuoustransmission determination for subframes and frames. Example method 1000may be implemented by the systems described in FIGS. 1, 2, 3, and/or 4.Initially, it is assumed the traffic load is high for this example, andit is in state 0. Its SubState and WaitingTime are also set to 0. Inthis state, the subframe and the frame are not DTXed. For each frame,the traffic load is estimated first. If it is below (TH(0)−HY(0)) forWT(0) time, it will move to state 1. Otherwise, it will stay in thisstate.

When the state corresponds to medium traffic load, 2^(k) number ofsubframes are DTXed. When the measured traffic load is below(TH(k)−HY(k)) for WT(k) time, it will move to state=k+1. When themeasured traffic load is above (TH(k) HY(k)) for WT(k) time, it willmove to state=k−1. If the measured traffic load is between (TH(k)−HY(k))and (TH(k)+HY(k)), it will stay in this state.

When the state corresponds to the low traffic load, the odd frames aswell as eight subframes of the even frames are DTXed. When the measuredtraffic load is above (TH(4)+HY(4)) for WT(4) time, it will move tostate 3. Otherwise, it will stay in this state.

For a certain State k, the value of SubState indicates the relativetraffic load. When TrafficLoad is between (TH(k)−HY(k)) and(TH(k)+HY(k)), it is set to 0. When TrafficLoad is above (TH(4)+HY(4)),it is set to 1. When TrafficLoad is below (TH(k)−HY(k)), it is set to−1. To reduce inter-cell interference, the subframe level DTX patternscan be randomized for different frames.

FIG. 11 is a diagram illustrating radio frame levels. Example frames1100 may be examples of frame structure used by the systems described inFIGS. 1, 2, 3, and/or 4. FIG. 11 illustrates frames 110, subframes 1120,and symbols 1130. Certain frames 1110, subframes 1120, and symbols 1130are depicted as being allocated for DTX.

FIG. 12 is a flowchart illustrating example embodiments of discontinuoustransmission for a mobile phone network node. In certain embodiments,the example method of FIG. 12 may be implemented by the systemsdescribed in FIGS. 1, 2, 3, and/or 4. Example method 1200 may begin atstep 1202, where radio network node 120 may determine traffic load.Radio network node 120 may do this by using traffic engine 260 todetermine how a predicted traffic load (TL) may compare to certaintraffic load thresholds (e.g., T1, T2). For example, T1 may represent alow traffic load threshold and T2 may represent a high traffic loadthreshold. If TL exceeds T2, then it may be determined that traffic loadis high and the example method may proceed to step 1203. If TL exceedsT1, but not T2, it may be determined that traffic load is medium and theexample method may proceed to step 1220. Otherwise, if TL is below T1,then the example method may proceed to step 1234.

At step 1203, radio network node 130 may initiate DTX at the symbollevel. Next, at step 1204, radio network node 130 may queue data. Forexample, radio network node 120 may queue data in data queue 250. Atstep 1206, radio network node 130 may determine traffic priority for thequeued data. For example, radio network node 120 may use traffic engine260 to determine traffic priority for data queued in data queue 250. Theexample method may then proceed to step 1208 where radio network node120 may determine a resource element estimation. As an example, radionetwork node 120 may use scheduling engine 280 to determine a resourceelement estimation of data in data queue 250. Next, at step 1212, radionetwork node 120 may determine whether low priority data was allocatedto the last symbol selected to carry data. If it is determined that lowpriority data may have been allocated to the last symbol selected tocarry data, then the example method may return to step 1204 where thelow priority data allocated to the last symbol may be re-queued in dataqueue 250. Otherwise, the example method may proceed to step 1214.

At step 1214, radio network node 120 may determine whether more symbolsmay be allocated for DTX. If so, the example method may return to step1204. Otherwise, the example method may proceed to step 1216 where radionetwork node 120 may set at least one hit in a PDCCH messagecorresponding to the at least one symbol allocated for DTX. For example,radio network node 120 may use message engine 270 to set the at leastone bit to correspond to the at least one symbol allocated for DTX. Incertain embodiments, extra bits may be added to PDCCH messages to signalwhich symbols are in DTX. According to some embodiments, four bits maybe added and may represent any number of symbols that may be in DTX. Ifthree bits are added, then up to eight symbols can be signaled to be inDTX. In other embodiments, only two bits may be added to the PDCCHmessage to signal the DTX cases for one symbol, two symbols, foursymbols, and eight symbols. The example method may then continue to step1218 where radio network node 120 1218 may determine whether it shouldcontinue DTX allocation. If yes, then the example method may return tostep 1202. Otherwise, the example method may end.

If the determined traffic load is at a medium level, then the examplemethod may proceed starting at step 1220 where radio network node 120may initiate DTX at a subframe level. The example method may proceed tostep 1222 where a subframe is selected for analysis to determine whetherit should be used for DTX. At step 1224, radio network node 120 maydetermine whether the particular subframe includes a broadcast message.If the subframe includes a broadcast message, then the example methodmay not use that subframe for DTX and may return to step 1222 whereanother subframe may be selected for analysis. Otherwise, the examplemethod may proceed to step 1226. At step 1226, radio network node 120may determine whether the particular subframe includes a synchronizationmessage. If the subframe includes a synchronization message, then theexample method may return to step 1222. Otherwise the example method mayproceed to step 1228 where the particular subframe is allocated for DTX.For example, radio network node 120 may use DTX engine 290 and/orscheduling engine 280 to allocate the particular subframe for DTX. Theexample method may proceed to step 1230 where radio network node 120 maydetermine whether or not to allocate more subframes for DTX. If moresubframes may be allocated, then the example method may proceed to step1222 where another subframe is selected for analysis.

Otherwise, the example method may proceed to step 1232 where radionetwork node 120 may set at least one bit in a broadcast messagecorresponding to the at least one subframe allocated for DTX. Forexample, radio network node 120 may use message engine 270 to set the atleast one bit to correspond to the at least one symbol allocated forDTX. In certain embodiments there may be ten subframes in a radio frame.In such embodiments one subframe may include a broadcast message and onesubframe may include a synchronization message (both of which are notsubject to DTX). Extra two bits in the broadcast message can be used toidentify how many of the remaining subframes are DTXed. For example,radio network node 120 may use message engine 270 and/or schedulingengine 280 to set the bits to “00” to indicate no subframes are DTXed,“01” to indicate two subframes are DTXed, “10” to indicate foursubframes are DTXed, and “11” to indicate that eight subframes areDTXed. The example method may then proceed to step 1218 (discussedpreviously).

If the determined traffic load is at a low level, then the examplemethod may proceed starting at step 1234 where DTX may be initiated atthe frame level by radio network node 120. Next, at step 1236, radionetwork node 120 may select at least one frame for DTX. For example,radio network node 120 may use DTX engine 290 and/or scheduling engine280 to do this. At step 1238, radio network node 120 may then set atleast one broadcast message corresponding to the at least one frameselected for DTX. In certain embodiments, one bit may be used in abroadcast message to indicate if odd frames are on or off. In such anembodiment, radio network node 120 may use message engine 270 to setthis bit. The example method may then proceed to step 1218, discussedabove.

Modifications, additions, or omissions may be made to the systems andapparatuses disclosed herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components.Additionally, operations of the systems and apparatuses may be performedusing any suitable logic comprising software, hardware, and/or otherlogic. As used in this document, “each” refers to each member of a setor each member of a subset of a set.

Modifications, additions, or omissions may be made to the methodsdisclosed herein without departing from the scope of the invention. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Accordingly, the above descriptionof the embodiments does not constrain this disclosure. Other changes,substitutions, and alterations are possible without departing from thespirit and scope of this disclosure, as defined by the following claims.

The invention claimed is:
 1. A mobile phone network node operable to:determine traffic load associated with a mobile phone network; andinitiate discontinuous transmission at a first one of a frame level, asubframe level, and a symbol level, based at least in part upon acomparison of the traffic load to a first threshold, wherein the mobilephone network node is operable to initiate discontinuous transmission atthe symbol level by: determining whether a symbol includes a referencesignal; using the symbol for discontinuous transmission if the symboldoes not include the reference signal and no data is allocated to thesymbol.
 2. The mobile phone network node of claim 1, wherein the mobilephone network node is further operable to initiate discontinuoustransmission at a second one of a frame level, a subframe level, and asymbol level, based at least in part upon a comparison of the trafficload to a second threshold.
 3. The mobile phone network node of claim 2,wherein the mobile phone network node is further operable to initiatediscontinuous transmission at a third one of a frame level, a subframelevel, and a symbol level, based at least in part upon a comparison ofthe traffic load to a third threshold.
 4. The mobile phone network nodeof claim 1, wherein the traffic load is determined based at least inpart upon a daily traffic load and an instant traffic load.
 5. Themobile phone network node of claim 1, further operable to allocate datato the symbol that includes the reference signal.
 6. The mobile phonenetwork node of claim 5, wherein the mobile phone network node operableto allocate data to the symbol that includes the reference signalcomprises the mobile phone network operable to allocate high prioritydata before low priority data.
 7. The mobile phone network node of claim1, wherein the mobile phone network node operable to initiatediscontinuous transmission at the first one of a frame level, a subframelevel, and a symbol level comprises the mobile phone network nodeoperable to initiate discontinuous transmission at the subframe levelby: determining whether a subframe includes a broadcast message;determining whether the subframe includes a synchronization message; andusing the subframe for discontinuous transmission if: the subframe doesnot include the broadcast message; and the subframe does not include thesynchronization message.
 8. The mobile phone network node of claim 1,wherein the mobile phone network node operable to initiate discontinuoustransmission at the first one of a frame level, a subframe level, and asymbol level comprises the mobile phone network node operable toinitiate discontinuous transmission at the frame level by: indicating atleast one frame to be used for discontinuous transmission by setting atleast one bit in a broadcast message to correspond to the frame.
 9. Adiscontinuous transmission method for an Evolved Node B comprising:determining traffic load associated with a mobile phone network;initiating discontinuous transmission at a first one of a frame level, asubframe level, and a symbol level, based at least in part upon acomparison of the traffic load to a first threshold, wherein initiatingdiscontinuous transmission at the symbol level comprises initiatingdiscontinuous transmission at the symbol level by: determining whether asymbol includes a reference signal; and using the symbol fordiscontinuous transmission if the symbol does not include a referencesignal and no data is allocated to the symbol.
 10. The method of claim9, further comprising initiating discontinuous transmission at a secondone of a frame level, a subframe level, and a symbol level, based atleast in part upon a comparison of the traffic load to a secondthreshold.
 11. The method of claim 10, further comprising initiatingdiscontinuous transmission at a third one of a frame level, a subframelevel, and a symbol level, based at least in part upon a comparison ofthe traffic load to a third threshold.
 12. The method of claim 9,wherein determining traffic load comprises determining traffic loadbased at least in part upon a daily traffic load and an instant trafficload.
 13. The method of claim 9, further comprising allocating data tothe symbol that includes the reference signal.
 14. The method of claim13, wherein allocating data to the symbol that includes the referencesignal comprises allocating high priority data before low priority data.15. The method of claim 9, wherein initiating discontinuous transmissionat the first one of a frame level, a subframe level, and a symbol levelcomprises initiating discontinuous transmission at the subframe levelby: determining whether a subframe includes a broadcast message;determining whether the subframe includes a synchronization message; andusing the subframe for discontinuous transmission if: the subframe doesnot include the broadcast message; and the subframe does not include thesynchronization message.
 16. The method of claim 9, wherein initiatingdiscontinuous transmission at the first one of a frame level, a subframelevel, and a symbol level comprises initiating discontinuoustransmission at the frame level by: indicating at least one frame to beused for discontinuous transmission by setting at least one bit in abroadcast message to correspond to the frame.
 17. A discontinuoustransmission system comprising: a memory; and a processor operable to:determine traffic load associated with a mobile phone network; andinitiate discontinuous transmission at a first one of a frame level, asubframe level, and a symbol level, based at least in part upon acomparison of the traffic load to a first threshold, wherein theprocessor is operable to initiate discontinuous transmission at thesubframe level by: determining whether a subframe includes a broadcastmessage; determining whether the subframe includes a synchronizationmessage; and using the subframe for discontinuous transmission if: thesubframe does not include the broadcast message; and the subframe doesnot include the synchronization message.
 18. The system of claim 17,wherein the processor is further operable to initiate discontinuoustransmission at a second one of a frame level, a subframe level, and asymbol level, based at least in part upon a comparison of the trafficload to a second threshold.
 19. The system of claim 18, wherein themobile phone network node is further operable to initiate discontinuoustransmission at a third one of a frame level, a subframe level, and asymbol level, based at least in part upon a comparison of the trafficload to a third threshold.
 20. The system of claim 17, wherein theprocessor is operable to determine traffic load based at least in partupon a daily traffic load and an instant traffic load.
 21. The system ofclaim 17, wherein the processor is further operable to: determinewhether a symbol includes a reference signal; and allocate data to thesymbol that includes the reference signal.
 22. The system of claim 21,wherein the processor operable to allocate data to the symbol thatincludes the reference signal comprises the processor operable toallocate high priority data before low priority data.
 23. The system ofclaim 17, wherein the processor operable to initiate discontinuoustransmission at the first one of a frame level, a subframe level, and asymbol level comprises the processor operable to initiate discontinuoustransmission at the frame level by: indicating at least one frame to beused for discontinuous transmission by setting at least one bit in abroadcast message to correspond to the frame.
 24. The processor of claim17, wherein the processor operable to initiate discontinuoustransmission at the first one of a frame level, a subframe level, and asymbol level comprises the processor operable to initiate discontinuoustransmission at the symbol level by: determining whether a symbolincludes a reference signal; and using the symbol for discontinuoustransmission if the symbol does not include a reference signal and nodata is allocated to the symbol.